Justin Bieber serenaded a couple on their honeymoon. The 'Boyfriend' hitmaker was vacationing in Bora Bora in French Polynesia when he came across bride Katie Wollesen and her new husband and sang for them as they sat down to eat. But the evening then took a more raucous turn as he joined them in a drinking game. Posting a picture on Twitter of herself and a female pal, Katie wrote: "Thank you @justinbieber for serenading us at dinner, challenging us in flip cup, and leading the winning team in the first annual coco bowl! #honeymooninwiththebiebs.(sic)" Justin replied: "not sure what face I'm making but.. Lol. Nice meeting u and happy honeymoon :) (sic)" The 21-year-old singer also shared a photo of himself with the newlyweds and other pals on his Instagram, in which he was carried topless by the group.